Signaling device for telephone systems.



No. 772,782. PATENTED OCT. 18 1904.

H. T. GBDERGREN. v SIGNALINGEDEVICE. FOR. TELEPHONE SYSTEMS.

APPLICATION FILED JAN. 28, 19.02.

NO MODEL.

UNITED STATES.

c Patented October 2L8, 1904.

HENRIK THORE oEDEReREN, OF sTooKHoLM, SWEDEN.

SIGNALING DEVICE FOR TELEPHONE SYSTEMS- SPECIFICATION forming part of Letters Patent No. 772,782, dated October 18, 1904.

' Application filed Tannary 28, 1902. Serial No. 91,576. (No model.)

To all whom it may concern:

Be it known that I, HENRIK TI-IORE CEDER- GREN, a subject of the King of Sweden and Norway, residing in Stockholm, Sweden, have invented certain new and useful Improvements in Signaling Devices for Telephone Sys- 'tems, of which the followingis a Specification.

This invention relates to signaling means employed in telephone systems wherein a central battery is employed and wherein a linerelay controlled by the subscriber is energized as long as the line of the subscriber is engaged. The characteristic feature of the invention re- "sides in the fact that the said relay controls the calling-signal, as well as the clearing-out signal, in such a manner that acurrentpassing through the calling-signal will be closed by the armature of the said relay at the calling of the exchangethat is, as the subscriber removes the telephone from the 'switchhookand that when the current through the same relay is interrupted as the subscriber hangs up the telephone on the hook and the armature then returns to its normal position the relay will effect such an alteration of the current passing through a clearing-out relay inserted in the third cord conductor that the relay last mentionedputs the clearing-out signal into operation. By arranging" the clearingout relay in the third cord conductor a con- 'siderable diminishing of the load of the conversation=transmitting current is efiected.

The invention is illustrated diagrammatically in the accompanying drawing, wherein the same is shownapplied to a telephone system provided with a central battery and with inductive resistances inserted between each line and the battery.

A and B designate two subscribers apparatus, and L L are two lines leading to the exchange, where connections are made, respectively, to the branched jacks J and J ductive resistances I I and l I are inserted In-v cords are inserted condensers K K The resistancesI and I are arranged as relays.

The connections in the subscribers instrument are of the well-known type where when speaking is not going on the bell and a con As seen from the drawing, the arrangements of the cord-circuit, as well as of each subscribers line, are entirely symmetrical. Forthat reason it is suflicient in the following description of the invention only to explain one side i of said cord circuit and one subscribers line.

As seen from the drawing, the armature C6 of the relay 1 bears when excited upon two contacts 70 A wire 5 connects the contact k with the receiving-stud 70 for the armature a of the relay R The signal S which may be of any suitable kind, is connected with the armature a at one side and with the battery B at the other. The contact in is joined to the relay R by means of a wire 6, and awire 7 leads from the other end of said relay to the test-springs f of the line. The armature a is connected with the other pole of the battery B by means of a wire 8, said pole being connected to earth. In the third cord condoctor a relay R is inserted, said conductor being also connected with the battery. The armature (b of said relay closes and breaks the circuit through the clearing-out signal S when the plug P is lifted from the keyboard, and thus the contact controlled by said plug, is closed. As the drawing is diagrammatic, it may be of advantage to explain that the contact 2 is hinged and has aspring which tends to hold its lower end or tail in contact with a terminal contact-piece 9 but when the plug P is moved down in front of the head on p the connection with p is broken.

The operation of the invention is as follows: In order to call the exchange, the subscriber removes the telephone from the switchhook. Current then passes from the battery B through the wire 2, the relay 1, one branch of the subscribers line, the switch-hook, the

receiver and the transmitter, the other branch of the subscribers line, the inductive resistance I, and the wire 1 back to the battery. The relay I is then eXcitedc'. a, it attracts the armature a. A current-circuit is now closed through the wire 9, the lamp S, the Wire 10, the armature (t the contact 1: the Wire 5, the contact 73, the armature and the Wire 8. The lighting of the lamp S indicates the call. Now the operator inserts the plug P into the proper jack J, whereby the following circuit is established: the battery B, the wires 11 12 13, the relay R the wire 14, the plug P, the test-spring and the spring f, the wire 7, the relay R the wire 6, the contact is, the armature c, and the wire 8. The relay R now attracts its armature I m whereby the circuit is broken through the the signal S closed by the contact 32 at p as soon as the plug was lifted from the keyboard, is thus broken by the armature (f. In consequence whereof the lamp S will not be lighted.

At the end of the conversation the subscriber hangs up the telephone on the hook. The current through the relay 1 is thereby interrupted. The armature of the same returns to its normal position and breaks in its turn the circuit through the relay R The contact is is thereby closed, and the lamp will be lighted and indicate that disconnection is to be made. Consequently the operator removes the plug from the spring-jack. IVhen the plug has been returned to the keyboard, the contact 1) is interrupted and the lamp S extinguished.

In the drawing the signals are shown as incandescent lamps; but evidently any other suitable kind of signals may be used, and in the practical execution of the invention the arrangements shown in the drawing may be modified in many respects without exceeding the limits of the invention defined in the claims.

Having thus described my invention, 1 claim 1. In a signaling means for the purpose specified, the combination with a relay I, in the subscribers circuit, the relay R connected with the test-line 7, the said test-line, the relay R in the cord-circuit of the system and so connected that the insertion of the plug of the cord in its corresponding jack connects the relay R in series with the relay R. through the test-line 7, the clearing-out signal S", its circuit, and means whereby the relay R controls the last-named circuit, said relay R" being connected during theconversation, with the arn'iature a of the relay 1 so that the contact of relay will be closed when at the end of the conversation the relay I becomes inactive and the circuit through its armature 0 becomes broken.

2. In a signaling means for the purpose specified, the combination with the relay 1 in the subscribers circuit, the relay R connected with the test-line 7, the said test-line the relay R in the cord-circuit of the system and so connected that the insertion of the plug of the cord in its corresponding jack connects the relay in series with the relay R and the armature a of the relay 1., the clearingout signal S its circuit, and means whereby the relay R when excited, breaks the lastnamed circuit, said circuit being closed when the relay 1 becomes inactive.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

\Vitnesses:

Go'rTLIEB PrL'rz, K. F. \VINoRAN'rz. 

